This application is for a new (type 1) PHS Institutional National Research Service Award to prepare fellows for an academic career in Hematology at the University of California, Los Angeles. The proposal is for 3 fellowship slots in the first year and 4 thereafter to support research programs in years 2 and 3 of a fellowship in Hematology/Oncology. Support is not requested for the first year's clinical experience, which provides extensive training through inpatient and outpatient Hematology and Oncology services at the Clinical Health Sciences Center of UCLA and at affiliated hospitals at the Wadsworth VA and at the Los Angeles Orthopaedic Hospital. After completion of the first (clinical) year, the trainee will begin his or her research experience in the chosen field and with the appropriate faculty mentor. The faculty consists of 21 scientists, about equally divided into 3 research foci, namely, hematopoiesis and stem cell biology, lymphocytes and host defense and hemostasis/thrombosis and vascular biology, each research focus of which is directed by a specialist in that field. All of the mentors have peer-reviewed Federal funding (20 of 21 with NIH grants), demonstrated success in training doctoral and/or post-doctoral research fellows, and experience in collaborative translational projects. Highest priority for acceptance of fellows into the program will be given to those whose goals are towards attainment of a PhD degree as part of the Department of Medicine Specialty Training and Advanced Research (STAR) Program, to those who already have dual MD/PhD) degrees, and to fellows with express interest in academic careers and experience in laboratory-oriented research. Strong efforts will be made to recruit fellows from underrepresented minority groups, especially through functional interactions with Drew University of Medicine and Science and the Martin Luther King Hospital in Los Angeles. Research seminars, work-in-progress sessions, and scientific retreats will afford special opportunities for selection of future mentors by fellows and for scientific interchange and project development. The program offers and independently supports additional research training beyond year 3 for those trainees who desire further experience to make the transition to academic investigator. A core curriculum includes required attendance in the "Clinical Research Course", which covers subjects on research design and analysis, ethics, regulatory issues, grant preparation and responsible conduct of research. The progress of fellows towards completion of their work will be monitored by regular and formal evaluations by the Steering Committee, which includes 4 PhD's among the 6 members, in concert with each fellow's mentor. The training of academic hematologists with expertise in basic, clinical and translational research is an important priority for academic medical centers and this application seeks support for the pivotal 2-year period between clinical training and an eventual career in academic hematology.